The present disclosure relates to a method in which a plasma is used for energetic excitation of a reactive etching gas. The etching gas serves for anisotropically etching a recess. The recess is for example a trench, in the case of which, at the opening edge, one lateral dimension is at least twice as large as a lateral dimension lying transversely at an angle of 90° with respect thereto, or a hole, in the case of which, at the opening edge, one lateral dimension is at most twice as large as a lateral dimension lying transversely at an angle of 90° with respect thereto. In the case of a hole, the two lateral dimensions are preferably equal in size. The opening is oval or rectangular in the case of a trench. The opening is oval, circular, rectangular or square in the case of a hole. Both holes and trenches are often referred to as trenches. The etching is more difficult in the case of holes than in the case of trenches since it is more difficult for the etching gases to reach the bottom of a hole in comparison with a trench having the same depth and the same width. Examples of recesses in micromechanics are furthermore recesses around beams, combs or tongues.